1. Field of the Invention
The present invention relates in general to the field of user inputs to an information handling system, and more particularly to a system and method for communication of keyboard and touchpad inputs as HID packets embedded on a SMBus.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems typically allow user inputs through a number of different types of devices. Most common is an external keyboard or external mouse that communicates user inputs as electrical signals through a wired or wireless connection to a port of the information handling system. For instance, a keyscan matrix identifies the position of a keystroke by a user based on an electrical signal communicated through a USB interface. Typically, a microcontroller in the chipset of the information handling system converts the keystroke into a Human Interface Device (HID) packet that is made available for use by components of the information handling system. However, user interfaces provided to an information handling system may originate from input devices located at a variety of locations near or far from the information handling system. Often, server information handling systems receive commands as keystrokes entered remotely through a network connection, such as through a network interface card. In contrast, portable information handling systems typically have integrated keyboards and integrated pointing devices, such as touchpad pointing devices, that are physically built into the housing of the information handling system along with the processing components.
One difficulty with integration of a keyboard and pointing device into a portable information handling system is that a bundle of wires is used to communicate signals from the keyboard to the motherboard of the information handling system and a separate set of wires is used for the pointing device. These separate sets of wires are bulky and thus have lead to movement in the industry to combine the keyscan function and the pointing device input detection at the location of the integrated pointing device in portable information handling systems.
Another difficulty that arises with different locations of user input devices is that hackers sometimes attempt to attack the security of information handling systems by entering simulated keystrokes and pointing device inputs through a network connection. In order to counter such attacks, industry has attempted to develop a “trusted” architecture that prevents remote access to certain information handling system functions. Generally, a trusted architecture prevents remote access to certain secured components of an information handling system, such as internal motherboard buses, like system management buses, such as the SMBus, the SPI bus and the I2C bus. One proposed trusted architecture is a trusted mobile keyboard controller that recognizes that inputs by users through integrated input devices, such as the integrated keyboard and pointing device of a portable computer, have greater security. By communicating inputs from integrated user interface devices and other trusted information through a proposed LPC bus at specific cycles, information handling systems are able to physically restrict remote access to certain functions.